THE EXCRETORY SYSTEM

Excretion is the removal of wastes that are made in the body cells.

THE EXCRETORY ORGANS

• Lungs (carbon dioxide and water vapour)
• Kidneys (urea, water and salts)
• Skin (water and salts)

THE EXCRETORY ORGANS

THE URINARY SYSTEM

• Made up of the following parts:
• The kidneys
• The renal arteries and renal veins
• The ureters
• The blader and The urethra

The function of the urinary system is to get rid of urea, water and salts.

URINE

• The kidneys make urine by filtering the blood.
• Urine is made up of urea, water and salts.
• Urine is stored in the bladder.
• The urethra carries urine out of the body.

REVISION QUESTIONS

• What are the three excretory organs?
• What is excreted through the skin?
• What substances is urine made of?
• How do the kidneys make urine?
• What is urine carried out of the body through?

ANSWERS

• Lungs, kidneys and skin.
• Water and salts.
• Urea, water and salts.
• By filtering the blood.
• Urethra.

FUN FACTS

• The bladder is as big as your brain.
• The skin acts as a sponge for oxygen.
• The kidneys are half the size of your bladder.
• The ureter is the size of a peice of spaghetti.
• As you urinate your bladder shrinks.